In the field of photomechanical processes, there is a demand for light-sensitive materials having satisfactory image reproducibility of originals, stability of processing solutions, and simplification of replenishment, in order to cope with the recent diversity and complexity of printed materials.
In particular, originals in line work comprise photo-composed letters, hand-written letters, illustrations, dot prints, etc., and thus contain images having different densities or line widths. There has therefore been a keen demand to develop a process camera, a light-sensitive material or an image formation system which enables one to reproduce the original with good reproducibility. In the photomechanical process of catalogues or large posters, on the other hand, enlargement or reduction of a dot print is widely conducted. When a dot print is enlarged in plate making, the line number becomes small and the dots are blurred. When a dot print is reduced, the line number/inch ratio becomes larger and the dots become finer than the original. Accordingly, an image formation system having a broader latitude has been needed to maintain reproducibility of halftone gradation.
A halogen lamp or a xenon lamp is employed as a light source of a process camera. In order to obtain photographic sensitivity to these light sources, photographic materials are usually subjected to orthochromatic sensitization. However, orthochromatic photographic materials are more susceptible to the influences of chromatic aberration of the lens and thus susceptible to image quality deterioration. The deterioration is conspicuous when using a xenon lamp as a light source.
Known systems meeting the demand for a broad latitude include a method of processing a lith type silver halide light-sensitive material containing silver chlorobromide (containing at least 50% of silver chloride) with a hydroquinone developing solution having an extremely low effective sulfite ion concentration (usually 0.1 mol/l or less). One may obtain thereby a line or dot image having high contrast and high density in which image areas and non-image areas are clearly distinguished. According to this method, however, development is extremely unstable against air oxidation due to the low sulfite concentration of the developing solution. Hence, various efforts and devices are required to stabilize the developing activity and, at the present time, the processing speed is considerably low thereby reducing working efficiency.
There has thus been a demand to find an image formation system which eliminates the image formation instability associated with the above-described lith development system and provides an ultrahigh contrast image by using a processing solution having satisfactory preservation stability. In this connection, it has been proposed to process a surface latent image type silver halide photographic material containing a specific acylhydrazine compound with a developing solution having a pH between 11.0 and 12.3 and containing at least 0.15 mol/l of a sulfite preservative and thereby exhibiting satisfactory preservation stability to form an ultrahigh contrast negative image having a gamma value exceeding 10, as described in U.S. Pat. Nos. 4,166,742, 4,168,977, 4,221,857, 4,224,401, 4,243,739, 4,272,606, and 4,311,781. This new image formation system is characterized by the fact that silver iodobromide and silver chloroiodobromide as well as silver chlorobromide, are applicable thereto, whereas the conventional ultrahigh contrast image formation systems are only applicable to photographic materials comprising silver chlorobromide having a high silver chloride content.
While the above-described image formation system exhibits excellent performance in dot quality, stability of processing, rapidness of processing, and reproducibility of originals, a system which provides further improved reproducibility of originals has been desired in order to cope with the recent diversity of printed materials.
An attempt to broaden gradation reproducing area has been made using a light-sensitive material containing a redox compound capable of releasing a development inhibitor upon being oxidized as described in JP-A-61-213847 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") JP-A-62-260153, JP-A-64-88451, JP-A-64-72140, and U.S. Pat. No. 4,684,604. However, when in an ultrahigh contrast image formation system using a hydrazine derivative, these redox compounds are employed in light-sensitive materials in amounts sufficient for improving reproducibility of line image and reproducibility of dot image, a portion of development inhibitors released during development are discharged from the light-sensitive materials. During continuous processing of a large amount of the light-sensitive materials containing these redox compounds the development inhibitors accumulate in the developing solution. As a result, when a light-sensitive material is subjected to development processing using such a fatigued developing solution, the capacity to make a high contrast is damaged and a decrease in sensitivity occurs. Particularly, when one automatic developing machine is employed for development of light-sensitive materials containing such redox compounds together with other light sensitive materials (for example, those for photographing, those for contact printing and those for a scanner), the photographic properties of such other light-sensitive materials are adversely affected.
Therefore, a sufficiently large benefit cannot be obtained, or only a closed system wherein light-sensitive materials and developing solutions to be used are restricted to a narrow range since the amount of the redox compound used is limited. Thus, there has been a desire to solve such problems.